look up canadian affair and book flights through them. They fly a couple of times a day from gatwick and I think they might also have some flights from heathrow. The flight will be a charter flight with a company called air transit...it is a budget airline. Your other options are Air Canada and BA,both fly from heathrow.
apologies if this isn't considered long haul I'm an inveterate traveller; I'm determined to visit dSis on Toronto this summer or autumn, she's only got a 1yr visa, we are low on funds so need flights as cheaply as comfortably as possible, baby just turned 8m, I'm aware iv just risked jinxing it now so I'm relying on you all to give me some amazing tips to help me thanks x ps flying from a London airport, LHR or LGW I understand?